Electrical contact with screw terminal and pressure-lock terminal



June 13, 1967 R. G. MUNROE 3,325,?68

ELECTRICAL CONTACT WITH SCREW TERMINAL AND PRESSURE-LOCK TERMINAL FiledJune 1, 1965 INVENTOR. RONALD G. MUNROE BY lui mn A T TORNE Y5 UnitedStates Patent 3,325,768 ELECTRICAL CONTACT WITH SCREW TERMINAL ANDPRESSURE-LGCK TERMINAL Ronald G. Munroe, Old Bridge, N.J., assignor toEagle Electric Mfg. Co., Inc., Long island City, N.Y., a corporation ofNew York Filed June 1, 1965, Ser. lo. 460,330 8 Claims. (Cl. 33995) Thisinvention relates to an electrical contact which is combined with bothascrew terminal and an integral pressure-lock.

Pressure-lock terminals have recently become popular for home electricaldevices, particularly those which are designed for installation by ahouseholder. This is quite understandable because they are extremelyeasy to connect in circuit, requiring simply stripping the insulationofi the end of a conductor and thrusting the exposed tip of the metalcore into an opening in the insulating housing for the electricaldevice. Typical pressure-lock terminals are disclosed in United StatesLetters Patent Nos. 2,705,785 dated Apr. 5, 1955, and 2,952,831 datedSept. 13, 1960, it being understood that reference thereto is merelyexemplificative and not restrictive. However, pressure-lock terminals donot invariably provide an acceptable or even desirable electricalconnection.

Frequently electrical devices of the character described which includeelectrical terminals are installed behind a wall surface and in such acase it may be a violation of an electrical code to employ apressure-lock terminal connection. It also may be considered undesirablebecause a settling of a house might exert sufiicient pressure on such aconnection to open it, in which event the bare core of the electricalwire would be exposed and be the possible cause of a hidden shortcircuit. Furthermore, under some conditions, it may be desirable inaddition to connecting the wire system of a house to an electricaldevice, to make a further connection from such electrical device to afurther electrical device, in other words, to eifect a junction betweentwo wires at an electrical device. Pressure-lock terminals are notconstructed for the admission of two wires, nor do they in their presentform lend themselves readily to modification for this purpose. On theother hand, a screw type terminal provides an arrangement that canitself, or with suitable modifications, be employed to eifect aconnection between two metal wire cores. Hence, there will be occasionswhen it is desirable to have a pressure-lock terminal available andother occasions when it would be useful to have an electrical screwterminal available.

The present conventional type of pressure-lock terminal does not lenditself to combination with a screw terminal. A pressure-lock terminal ischaracterized by the provision of a cantilever-mounted spring tonguehaving a tip arranged near, and at an angle to, a stationary anvilthereby provide a narrow gap into which the tip of the metal core of anelectric conductor is thrust, the angle between the spring and the anvilon the side of the tongue at which the conductor is introduced beingacute so that the conductor can easily cam its way into and through thegap but will be engaged by the tip of the tongue acting as a retrogradecheck or spur that digs into the wire conductor to prevent itsaccidental withdrawal.

It has been the practice in present-day pressure-lock terminals to makethe cantilever tongue that is employed of light gauge spring stockinasmuch as the flexing action of the tongue must take place in crampedquarters and the tongue must not otter too much resistance to theintroduction of a metal conductor. Thus, in a duplex electricalreceptacle which is one popular site for pressurelock terminals thepressure-lock tongue has its tip adjacent the bridge that connects thetwo electrical contacts 3,325,768 Patented June 13, 1967 of thereceptacle and the tongue is in one piece with such bridge so that itmust experience an appreciable degree of angular movement for properoperation. Hence, it is particularly desirable that the tongue andbridge be of rather slight thickness in order to enable it to experiencethe requisite degree of flexing.

Due to the necessary lightness, that is to say, thin gauge of metal thatmust be used, to allow the tongue to flex under the foregoingcircumstances, it has not been possible until now to combine apressure-lock terminal with a screw terminal unless there additionallyis employed a stitfening piece of metal, such for instance as a smallsteel plate, which is clamped or welded to the bridge between thecontacts, which plate is sufficiently strong to be apertured and tappedfor reception of the terminal screw. Although it is not structurallyimpractical to use the extra metal plate in order to accomplish theabove described function, in a business where parts are made inextremely large quantities by mass production and where manufacturingcosts are under retail pressure for low pricing, the addition of theextra plate and its attachment to the bridge is not looked upon withfavor.

It is an object of the present invention to provide a combinedpressure-lock and screw terminal which is not subject to the foregoingdrawbacks.

It is another object of the invention to provide a combinedpressure-lock and screw terminal in which the pressure-lock terminal andthe means for threadably receiving the screw are unitary, i.e., of asingle piece.

It is another object of the invention to provide a device of thecharacter described constituting a combined unitary, that is to say, onepiece, contact, pressure-lock terminal and support for a terminal screw.

It is another object of the invention to provide a device of thecharacter described which is so designed that the pressure-lock terminalcan be made of heavier stock than presently is employed so that the samestock can serve to provide a tapped opening for the reception of aterminal screw.

It is another object of the invention to provide a device of thecharacter described which is so designed that the pressure-tongue isfashioned from what otherwise would be waste stock, so that the devicecan be made at a particularly low cost. In this latter connection it isobserved that in a combined contact and pressure-lock terminal, such asheretofore has been conventional, the pressuretongue was formed from anadditional width of stock which therefore gave rise to considerablewaste, the recovery value of which was negligible since it had to besold for reclaiming as scrap. On the other hand, pursuant to the presentinvention, where the pressure-tongue is arranged to be blanked out ofwhat otherwise would be scrap, an appreciable savings is effected.

It is another object of the invention to provide a device of thecharacter described in which, despite the consolidation of thepressure-lock with a screw terminal, said lock nevertheless is efiicientand elfective in operation and will provide an attachment to a wireconnector that is at least as firm as that presently etfected bypressure-lock terminals of light gauge stock.

Other objects of the invention in part will be obvious and in part willbe pointed out hereinafter.

The invention accordingly consists inthe features of construction,combinations of elements and arrangement of parts which will beexemplified in the device hereinafter described and of which the scopeof application will be indicated in the appended claims.

In the accompanying drawings in Which is shown one of the variouspossible embodiments of the invention,

FIG. 1 is a top plan view of a duplex receptacle employing combinedcontacts, pressure-lock terminals and screw terminals in accordance withthe present inven- 3 tion, said receptacle having one lateral half ofits top housing removed to show a part of the interior of the receptaclewith the associated combined contacts and terminals;

FIG. 2 is a cross-sectional view taken substantially along the line 22of FIG. 1;

FIG. 3 is an enlarged fragmentary cross-sectional view takensubstantially along the line 3-3 of FIG. 1 and illustrating theconstruction of the pressure-tongue, the cantilever-mounted base thereofand the anvil against which the pressure-tongue urges a bare metalconductor wire;

FIG. 4 is a perspective view of a combined unitary pair of contacts,pair of pressure-lock terminals, bridge and pair of mounts for terminalscrews, a fragment of one of the mounts being broken away to expose forillustrative purposes the tip of one of the pressure-tongues;

FIG. 5 is a top plan view of a band of metal stock showing the outlinesof successive blanks for devices of the present invention which will becut out therefrom; and

FIG. 6 is a side view of the receptacle.

In general, the several objects of the present invention are achieved bymaking the pressure-lock and contact .components of the instant devicefrom comparatively heavy electrically conductive sheet metal stockrather than the light stock that has been employed heretofore forpressure-lock terminals and contacts, such previous stock having beentoo light to conveniently provide a tapped bore for reception of a screwterminal. Particularly good results have been accomplished where thestock of the combined one-piece contacts and terminals constitutes extrahard brass approximately three one-hundredths of an inch in thickness.This is a rather stiif stock. It is much too heavy for use in apresent-day pressure-lock terminal of standard construction where itwould render the pressure-tongue too stiff to be flexed by introductionof a standard bare conductor wire. However, such heavy stiif brass stockis conventionally employed at the present time for electrical contactsthat do not have unitary pressure-lock terminals, i.e., for electricalcontacts in general and for electrical contacts that have screw typeterminals. Thus, the stock is sufiiciently flexible, even though stiff,for use as an electrical contact component. The requisite additionalflexibility, to wit: flexibility beyond that necessary for use as acontact, in order to employ this stock as a pressure-lock tongue, isobtained by spacing the cantilever-mounted base of the tongue aconsiderable distance from the anvil with which the tip of the tonguecooperates. Heretofore, as has been noted above, the anvil for thetongue conventionally has constituted the bridge which extended betweena pair of contacts of a duplex receptacle. In accordance with thepresent invention, the anvil now constitutes a flange adjacent thecontact which flange is spaced at the maximum practical distance fromthe cantilever-mounted base of the pressure-tongue. It has been foundthat within the dimensions prevailing in a duplex receptacle, suchspacing imparts sufficient flexibility to the stiff brass stock toenable the pressure-tongue to function properly.

Referring now in detail to the drawings, the reference numeral 10denotes a duplex bayonet plug receptacle which is a type of electricaldevice that can utilize the present invention to good advantage inasmuchas the housing of the device, save for its front face, is, in use,located behind a wall surface. Other electrical devices which also canefiicaciously employ the present invention are, by way of example,single and triple bayonet plug receptacles, screw base receptacles andwall switches.

The duplex receptacle 10 includes a housing -12 of;electricallynon-conductive material, e.g., a thermo-setting plastic such as aphenol-formaldehyde condensation resin. The housing is composed of a tophousing part 14 and a bottom housing part 16. These parts are molded toprovide the usual conventional external shape and a suitablesubstantially conventional internal shape which is proper to receive andsupport the contacts and terminals.

In particular, the top housing part 14 is formed with the customarypairs of bayonet-passing slots 18, two pairs of these slots beingincluded because the device is a duplex receptacle. Also present in theduplex receptacle herein illustrated, but not as a part of theinvention, are a pair of grounding slots 20. Thus the receptacle isdesigned to receive a plug, not shown, having a pair of parallel bayonetpower prongs of flat blade-like configuration and a third bayonetgrounding prong which may be of circular cross-section or of across-section in the form of a rectangle with one arcuate side.

The top housing part 14 is molded to include a central longitudinalseparator 22 and the bottom housing part to include a centrallongitudinal separator 24, said separators being interengaged internallyof the receptacle to subdivide the interior of the housing into twolongitudinal compartments 26. A portion of each compartment extends intothe bottom of the top housing part and the remainder into the top of thebottom housing part.

The separators 22, 24 are relieved for lightness and economy and also toaccommodate a mounting strap 28 and a grounding strap (not shown). Theends of the grounding strap include downwardly extending legs which formgrounding contacts 30, each of which is located slightly inwardly of adifferent grounding slot 20 so as to be engaged by a grounding pronginserted into the some. The grounding strap is made of a thin resilientelectrit ally conductive metal such as phospho-bronze.

The mounting strap is conventional and comprises plated iron sheet metalshaped to the usual form halving outwardly extending ends 32 configuredfor ready engagement to a structural element of a building or to a metaloutlet box. The central portion of the mounting strap passes between thetwo separators 22, 24 and said strap .is held in place by a metal rivet34 that extends through registered holes in the strap and the top andbottom housing parts. The same rivet also extends through the groundingstrap which is in face-to face contact "with the under surf-ace of themounting strap.

As is customary, the rivet is tapped for reception of a screw that isemployed to hold the escuthceon plate for the receptacle. Therebyagrounding connection is provided from the grounding contacts through therivet and mounting strap 28 to the outlet box which, in accordance withstandard practice, is grounded.

Located in each of the compartments 26, is a different contact-terminaldevice 36 embodying the present invention. Since these devices areidentical only one will be described.

Each device incldes a body portion constituting two co-planar flatshanks 38 separated by a deep locating notch 49 which is adapted toengage a locating ridge 42, transversely disposed in and molded inone-piece with the bottom housing part 16 so as to insure properlengthwise positioning of the contact-terminal device within thereceptacle. The two shanks 28 are firmly tied together by a junctionspan 44 in the form of a flat nib which projects upwardly and outwardlyaway from the shanks 38 in order to clear the top housing part 14. Thecorners of the bottom edge of the nib are in one-piece with the adjacentupper inside corners of the shanks 38 and indeed all parts of thecontact-terminal device are formed from a single piece of stock, thisbeing the comparatively heavy electrically conductive extra-hard brassstock to which reference heretofore has been made.

The flat shanks 38 are of rectangular shape and are in lengthwisealignment. The two said shanks together with the junction span jointlyform what will, upon occasion, hereinafter be referred to as acontact-bridge inasmuch as these three elements together constitute thatpart of the contact-terminal device which extends between, physicallyand electrically connects, and supports contacts at its ends. Forreference purposes, the different edges of each flat shank will bedesignated as follows: 38:: the inner side edge, 38b the bottom edge,38c the top edge and 3811 the outer side edge.

In said duplex receptacle, each of the side walls 45 of the bottomhousing part is formed with a closely positioned pair of broad deepthrough notches 46, each of which extends down from an open mouth at thetop edge of the wall. The notches are separated by the locating ridge42. The flat shanks 33 are disposed adjacent the inner face of the sidewall 45 and thus are exposed to a substantial extent through the notches46. The inner edges 38a of the shanks rest against the side surfaces ofthe locating ridge.

The thus exposed portion of each shank 38 is centrally apertured toprovide an opening 48. Desirably the openings are initially formed to asmaller than required diameter, as by punching, and then subsequentlyare enlarged by a drawing pin which raises a squat annular flange on theinner surface of the shank. The opening 48 and the associated flange aretapped to receive a terminal screw 50. Thus, there are two such terminalscrews on each side of the duplex receptacle, each affiliated pair ofscrews being engaged to a different contact-terminal device and beingconnected to a different side of the electric line. These screws may beemployed to make an electrical connection from the house wiring systemto the contactbridges or they may be employed to effect an electricalconnection between two house wires at the receptacle or they may beemployed to effect an electrical connection from the receptacle to ahouse wire which supplies electrical energy to a different electricaldevice. It will be appreciated that in the foregoing manner a simplescrew-terminal has been consolidated into the contact-terminal device36. The screw-terminal is readily and easily accessible and does notinterfere with either the contacts or the pressure-lock terminals soonto be described.

If desired, the tips of the screws 54) may be staked to preventinadvertent withdrawal of the same from the tapped opening 48.

It will be observed (see FIG. 1) that the powerprong receiving slots 18are spaced laterally inwardly from the side walls 45 of the bottomhousing part. Since the effectively plane contact-bridge lies againstthe internal surface of the associated side wall of the receptacle andsince the contact-bridge is in one-piece with the contacts, it isnecessary to provide the contact-terminal device with laterally inwardlyextending offset flange 52 at each end thereof, this being customary inthe art, to align the contacts with the slots. Each flat shank 38accordingly has an offset flange 52 formed in one-piece therewith at itsouter side edge 38d. The flanges are perpendicular to the shanks andextend inwardly from the edges 33d, said flanges serving as intermediateconventional supports connecting the contact-bridge wit-h contacts 54 atopposite ends of the device.

The contacts 54 may be of any desired structure which is such as tolocate contact elements in operable positions below the associatedpower-prong passing slots 18. Thus each contact may consist of only asingle contact blade or, as shown, it may consist of a pair of opposedcontact blades, the latter being more customary because it provides amore certain and higher physical pressure engagement between the contactand a power prong. The particular contact structure illustrated isdesirable because it enables a minimum width of band to be employed forblanking of the devices 36 therefrom; accordingly, its construction willbe detailed.

The contact 54 includes two opposed blades, to wit: an outer blade 56and an inner blade 58 (see FIG. 4). Said blades have substantialportions thereof mutually coextensive and are located behind anaffiliated slot 18 so that a power prong will be in line with the zonebetween the blades. The outer blade 56 is parallel to the nearby sidewall of the receptacle. The inner blade 58 6 may likewise be parallelthereto but preferably, and as shown, is tilted at a slight angle to theouter blade so that the outermost edges of the blades touch one anotheras shown in FIGS. 1 and 4, While the opposite edges of the blades areslightly spaced apart. The upper ends of the blades have angled lead-intips 60 to cam an improperly introduced power prong into the zonebetween the blades. The outer blade 46 is connected by a right angledstub leg 62 to the edge of the offset flange 52. The inner blade 58 isconnected by a longer acutely angled leg 64 to the edge of the offsetflange. The two legs 62, 64 are respectively located at the upper andlow regions of the inner edge of the offset flange, that is to say, thetwo legs are at different non-overlapping elevations on thecontactterminal device. To increase the resiliency of the mounting ofthe inner blade 58, the leg 64 is longer than necessary to place theinner blade in juxtaposition to the outer blade and the additionallength is formed into a bight 66.

The usual dimple 68 is indented into the outer surface of the outerblade so as to raise a corresponding locking protuberance 70 on theinner face of said blade.

To aid in inhibiting longitudinal shifting of the contactbridge, the twooffset flanges 52 at the opposite ends of said bridge engage ribs 72, 73formed internally of the bottom housing part 16.

As thus far described, it will be apparent that the contact-terminaldevice has the approximate shape of a very shallow U with out-turnedtips at the ends of its legs. The base of the U constitutes thecontact-bridge which is composed of the pair of shanks 38 joined by thespan 44, the legs of the U constitute the offset flanges 52 and theout-turned tips at the ends of legs constitute the contact structure 54.The resemblance of the device to a shallow U is of importance inconsidering the arrangement now to be described for the construction ofpressurelock terminals 74.

It already has been pointed out that a pressure-lock terminalessentially is composed of two elements, to wit: an anvil and apressure-tongue. The anvil in the pressurelock terminal 74 is the offsetflange 52. The pressuretongue is denoted by the reference numeral 76 andbest can be seen in FIGS. 3 and 4.

The pressure-tongue is in the shape of an elongated narrow strip that isin one piece with the contact-terminal device and has a flat base 78extending from that part of the bottom edge 38b of the affiliated flatshank 38 which is next to the inner edge 38a. Said base 78 is orientedperpendicular to the plane of the flat shank. Except for the base 78 thepressure'tongue is unconnected to the edge 38!) so that it is free toflex. The pressure-tongue includes an arched portion 8% extending overapproximately and unitarily joined at one end to the base 78. Saidarched portion extends downwards, away from the shank and then curlsback toward the shank at its other end. From its said other end thearched portion tangentially runs into an intermediate reach 82 that liesat an angle of about 120 to the base 78 and crosses the bottom of theshank. The intermediate reach in turn supports a terminal reach 84 thatlies at an angle of about to the base so that said reach makes an angleof approximately 45 to the anvil 52.

The tip of the terminal reach is close to the offset flange (anvil) 52,the spacing therebetween being less than the diameter of the smallestbare conductor wire that will be used to make a connection to thereceptacle. Preferably, the corner of the tip which faces the anvil issubstantially square in order thereby to obtain an efficientpressure-locking effect.

The zone between the tip of the terminal reach and the anvil is spacedabout midway between the upper and lower edges 33c, 33!; of the shankand an opening 88 is formed in the bottom wall 86 of the bottom housingpart 16 in registry with said zone to admit a bare conductor wire 90. Aswill be seen in FIG. 3, when said wire is thrust into the opening 88 itwill be guided into the space he tween the terminal reach and the offsetflange due to the angled inclination of the reach 84. The bare conductorwire will force the reach away from the anvil so as to permit the wireto be introduced into the zone between the anvil and the corner of thetip of the terminal reach. Once the bare conductor wire is emplaced, asshown in FIG. 3, any force tending to withdraw it will cause thepressure-tongue to dig into the wire so that the tongue acts on aretrograde checking pawl which prevents withdrawal of the wire.

An unlocking opening 92 is formed in the base wall 86 alongside the wireinsertion opening 88 and in line with the intermediate reach 82 (seeFIG. 3). When it is desired to release a Wire held by the pressure-lockterminal, the tip of a slender rigid instrument, such as a screw driver,is inserted into the opening 92 and pressed against the intermediatereach, causing the terminal reach to flex away from the anvil andthereby releasing the wire 90 caught thereunder.

It will be observed that because of the substantial space whichconventionally is provided between the center of a contact-bridge and anoffset flange, the length of a pressure-tongue that extends over saidspace in a non-linear fashion, is sufliciently great to permit thetongue to flexreadily when a bare conductor wire end is pressed againstits terminus; this, despite the comparative heaviness and stiffness ofthe stock from which the contact-terminal device is fabricated and whichare required for proper formation of a tapped opening to receive athreaded terminal screw. The non-linear configuration of thepressuretongue between its base and its tip, and to which reference justhas been made, results from both the arched portion 80 which extendsfirst downwardly from the base and then back up toward the tip of thetongue and the location of the tip of the tongue high on the offsetflange, e.g., between /3 and /2 of the height of the flange from thebottom edge 38b.

In order to accommodate said arched downwardly protruding portion, thebottom wall 186 of the bottom housing part is locally depressed beneathsaid portion to include a well 94 shown in FIG. 3, one edge of the wellconstituting an edge of the unlocking opening 92.

The low point of the arched portion is disposed close to the bottomsurface of the well 94 and, preferably, will engage the same when idle.However the full length of the tongue, from its base to its tip, willflex when a wire is introduced.

Attention is directed to the fact that the unique structure and mountingof the pressure-tongue which enables it to cooperate with the offsetflange as a presure-lock has an additional advantage which is notapparent at first glance. This is that the pressure-tongue isconstituted from that part of the original band stock which otherwisewould be scrap, so that the pressure-lock tongue can be included in thedevice without increasing the width of band of sheet metal stockrequired, or the length along the stock for each device. To illustratethe foregoing, in FIG. 5 there is shown a short length of band stockwith a series of successive contact-terminal devices laid out in theflat thereon. The parts of the blank have been numbered in the samefashion as the corresponding parts of the finished device except for theopenings 96 which subsequently are enlarged and flanged to form thetapped openings 48. From inspection of FIG. 5 it will be seen that theleadin tips of the contact blades protrude above the top edges 380 ofthe flat shanks 38 and that the space between these tips which in partincludes the junction span 44 and which otherwise would be waste, isoccupied by the pressuretongues 74.

Also as seen in FIG. 5, the terminal reach 84 is somewhat narrower thanthe intermediate reach 82. Inasmuch as the intermediate reach is widerthan the offset flange, the reduction in width matches the width of theterminal reach to that of the offset flange.

It thus will be seen that there is provided a device which achieves theseveral objects of this invention and which is well adapted to meet theconditions of practical use.

As various possible embodiments might be made of the above invention,and as various changes might be made in the embodiment set forth, it isto be understood that all matter herein described or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

Having thus described my invention I claim as new and desire to secureby Letters Patent:

1. In a combined contact and pressure-lock terminal, a shank having abottom edge and a side edge, said edges being at right angles to oneanother, a flange on said side edge for connection with and support of acontact, said flange extending inwardly at right angles to said shankand constituting an anvil of a pressure-lock terminal, said terminalfurther including a pressure-tongue cooperating with said anvil, saidpressure-tongue including a base cantilever-connected to and extendinginwardly from the bottom edge of the shank remotely from the said sideedge and adjacent the opposite side edge, the entire length of saidtongue, except the base, being free of the shank, the tip of said tonguebeing angled upwardly away from the bottom edge of the shankto terminateclose to but spaced from the flange a distance therefrom less than thediameter of a bare conductor wire, said pressure-tongue including anintermediate section between the base of the tongue and the tip thereof,said intermediate section extending from the base of the tonguedownwardly away from the bottom edge of the shank and then reversing toextend upwardly and cross the bottom edge of the shank, said shank,flange and pressure-tongue being formed of a single piece of heavy stiffelectrically conductive sheet metal stock.

2. A combination as set forth in claim 1 wherein the intermediatesection includes an arched portion connected to the base and in excessof and less than 180 in length, said arched portion terminating at theend thereof remote from the base in an intermediate reach.

3. A combination as set forth in claim 2 wherein the intermediate reachis a tangential extension of the arched portion.

4. A combination as set forth in claim 1 wherein the base of thepressure-tongue is perpendicular to the shank.

5. A combination as setforth in claim 4 wherein the base of thepressure-tongue is also perpendicular to the flange.

6. A combination as set forth in claim 1 wherein the shank isrectangular.

7. A combination as set forth in claim 1 wherein means is included todefine a tapped opening in the shank for reception of a terminal screw.

8. A combination as set forth in claim 1 wherein means is included todefine a tapped opening in the shank and wherein a terminal screw isengaged in said opening.

References Cited UNITED STATES PATENTS 9/1960 Ehrlich 339- 9/1961 Smith339164

1. IN A COMBINED CONTACT AND PRESSURE-LOCK TERMINAL, A SHANK HAVING ABOTTOM EDGE AND A SIDE EDGE, SAID EDGES BEING AT RIGHT ANGLES TO ONEANOTHER, A FLANGE ON SAID SIDE EDGE FOR CONNECTION WITH AND SUPPORT OF ACONTACT, SAID FLANGE EXTENDING INWARDLY AT RIGHT ANGLES TO SAID SHANKAND CONSTITUTING AN ANVIL OF A PRESSURE-LOCK TERMINAL, SAID TERMINALFURTHER INCLUDING A PRESSURE-TONGUE COOPERATING WITH SAID ANVIL, SAIDPRESSURE-TONGUE INCLUDING A BASE CANTILEVER-CONNECTED TO AND EXTENDINGINWARDLY FROM THE BOTTOM EDGE OF THE SHANK REMOTELY FROM THE SAID SIDEEDGE AND ADJACENT THE OPPOSITE SIDE EDGE, THE ENTIRE LENGTH OF SAIDTONGUE, EXCEPT THE BASE, BEING FREE OF THE SHANK, THE TIP OF SAID TONGUEBEING ANGLED UPWARDLY AWAY FROM THE BOTTOM EDGE OF THE SHANK TOTERMINATE CLOSE TO BUT SPACED FROM THE FLANGE A DISTANCE THEREFROM LESSTHAN THE DIAMETER OF A BARE CONDUCTOR WIRE, SAID PRESSURE-TONGUEINCLUDING AN INTERMEDIATE SECTION BETWEEN THE BASE OF THE TONGUE AND THETIP THEREOF, SAID INTERMEDIATE SECTION EXTENDING FROM THE BASE OF THETONGUE DOWNWARDLY AWAY FROM THE BOTTOM EDGE OF THE SHANK AND THENREVERSING TO EXTEND UPWARDLY AND CROSS THE BOTTOM EDGE OF THE SHANK,SAID SHANK, FLANGE AND PRESSURE-TONGUE BEING FORMED OF A SINGLE PIECE OFHEAVY STIFF ELECTRICALLY CONDUCTIVE SHEET METAL STOCK.